The invention concerns an electrode arrangement, in particular for the intracardial discharge of defibrillation pulses in the atrium or the ventricle of a heart, having an electrode line which in the region of its distal end has a plurality of electrically conductive surface portions as electrodes, which can be electrically connected by way of the electrode line to an electrical pulse-discharging device such as a defibrillator, cardioverter or pacemaker or the like.
Certain cardiac palpitations or arrhythmia phenomena, including in particular ventricular and atrial fibrillation, but possibly also accelerating tachycardia phenomena which have not yet passed into the state of fibrillation are electrotherapeutically treated with good prospects of success by applying short-duration electrical pulses or shocks to the sensitive cardiac tissue.
In that situation, in order rapidly to achieve termination of those life-threatening arrhythmia effects with a high level of certainty, relatively high voltages are conventionally applied and high levels of energy are supplied to the cardiac tissue, which in many cases results in tissue damage and serious stresses such as pain for the patient. In addition, in relation to implantable units, the provision of those high voltages and high energy levels requires expensive apparatus implementation with special structural and insulating elements, in particular powerful batteries and capacitors. Finally, electrode arrangements of large area were and still are used for transmitting the cardioversion energy to the cardiac tissue, and the production and implantation thereof involves a high cost level.
The design of cardioverters or defibrillators (hereinafter jointly referred to by the term “cardioverter”) and the associated electrode arrangements has been the subject of a drive for increasing perfection. In that respect, on the one hand numerous technical solutions have been proposed for ascertaining and providing, in the best possible differentiated fashion, the energy and voltage required for cardioversion of the specific cardiac arrhythmia phenomena involved as well as advantageous pulse shapes and sequences and on the other hand various electrode arrangements have been proposed, which were each considered advantageous from given respective points of view. In actual fact substantial practical improvements which have promoted the widespread practical use of implanted cardioverters or defibrillators and combined pacemakers/cardioverters have proven successful.
In the course of that development increasingly refined and powerful endocardiac defibrillation electrode lines have been described, which afford considerable advantages in terms of implantation and in regard to the operative risks, see for example WO/A-94/03233, EP-A 0 602 356 or the present applicants' prior application DE 196 26 352.2. The endeavours in that respect are inter alia along the lines of applying a cardioversion shock to larger areas of the cardiac tissue by the provision of a plurality of and/or large-area electrode on an endocardiac line, thereby to approximate the area of action of endocardiac electrode arrangements to that of subcutaneous or epicardiac surface electrodes.
With that background of the state of the art in mind, the object of the present invention is that of providing an electrode arrangement which permits advantageous defibrillation.